Drum-mill.



PATENTED JULY 18, 1905.

R. BENEKE. DRUM MILL.

APPLIGATION FILED JUNE 21'. 1904.

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Patented July 1s, 1,905.

PATENT OEEICE.

RlCHARD BENEKE, OF BROMBERG, GERMANY.

DRUM-MILL.

SPECIFICATION forming part of Letters Patent No. 794,843, dated July 18, 1905.

Application filed Jne 27, 1904. Serial No. 214,372.

To al/f lll/1,0m t may concern:

Beit known that I, RICHARD BENEKE, engineer, a subject of the King of Prussia, Emperor of Germany, residing at Mittelstrasse No. 6, Bromberg, Germany, have invented certain new and useful Improvements in Drum-Mills, of which the following is a specification.

My invention relates to an attachment for drum-mills, whereby the coarse material which does not pass through the sieve is returned to the grinding-drum. Prior apparatus of this kind in which the return-feed device is connected to the grinding-drum with positive motion and consists of curved channels or blades which scoop up the material that has fallen from the drum only opcrate successfully when the drum is driven at a strictly limited speed. At even only slightly higher speed the material sticks or holds to the blades, owing to the centrifugal force commencing to exercise an influence upon the material to be returned to the drum, whereby the action of the apparatus is seriously affected. The iniiuence of the centrifugal force is expressed, greatly to the disadvantage of proper operation, by the material no longer passing freely through the return-channels, but gradually collecting in layers at certain parts until the said channels are wholly choked.

The subject of the present invention is a return-feed device whereby the disadvantages referred to are overcome-that is to say, are not experienced in a drum-mill running at any speeds which occur in practice. The new device differs from prior apparatus for the same purpose, inasmuch as the curvev of blades or channels-that is, their conveying-faces-are interrupted in such manner that a depression or pocket is formed intermediate the two ends of the blades. The blade scoops up the material leaving the drum, lifts it to a certain extent, and then again lets it fall freely upon the depressed portion or pocket of the blade, which catches the material and conveys it back to the drum.

My invention is illustrated in the accompanying drawings7 in which- Figure 1 is a front elevation of the apparatus, and Fig. 2 a vertical section of a portion of a mill to which it is fitted.

The device consists of a casing a, secured to one end of the drum g, and therefore rotating at the same speed as the latter. Within this casing a number of blades are provided, the curve of which is interrupted,-

so that a depression or pocket c is formed in each blade.

The material falling out of the drum through the apertures h descends upon the sieves i and 7c in the ordinary manner, and coarse material remains lying upon the sieve k and passes into the casing a.

If the drum g and casing a are rotated, for example, in the direction of the arrow, Fig. 1, the material collecting in the casing a in consequence of the centrifugal force will be elevated to a certain extent by the wall of the casing a, where it will then remain until one of the blades b approaches it. Since these blades, as the drawing shows, run from the wall of the casing a toward the shaft of the latter, they will scoop up the material m and carry it upward in the direction of rotation of the casing, whereby the material 'm will gradually be conducted on the blades to the shaft until it has reached the free end of the blade, whereupon it will descend,falling freely. This material sliding from the blades b and then falling down has to be caught up and conducted into the interior of the drum g. For this purpose the blades are depressed, as shown, said depressions being so located that the blades enter under the material m, catching it up as it falls from the forward part b of the blades. The material descending into the depression or pocket of the blades thus slides down the latter and is returned to the interior of the drum by passing through apertures f in the boss 'rb-for instance, along screw-shaped wings or vanes Z.

The blades b are so curved that they do not impede the free fall of the material m when the mill has reached its highest or its normal speed.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-.

1. In a drum-mill, a device for returning IOO the coarse material to the drum, comprising a casing secured to the drum end, and blades located therein running from the periphery toward the center and presenting an uninterrupted curve by providing a depression or pocket in said blades, the blades scooping up the materialfand the depressed portion thereof conveying it back to the drum.

2. ln a drum-mill, a device for returning coarse material to the drum, comprising a casing secured to the drum-head, blades located therein running from the periphery Witnesses:

HENRY HAsPER, WOLDEMAR HAUPT. 

